The major product obtained when tert-butyl bromide is heated with sodium ethoxide is
 

tert-Butyl bromide (CH₃)₃CBr undergoes elimination when heated with sodium ethoxide (NaOEt).

Sodium ethoxide (NaOEt) is a strong base, which facilitates dehydrohalogenation (elimination of HBr) from tert-butyl bromide.

Mechanism:

1. The base (OEt^-) abstracts a proton (H⁺) from a beta-carbon adjacent to the carbon attached to the bromine atom.
2. The bromine atom leaves as bromide ion (Br^-).
3. A double bond forms between the beta-carbon and the carbon that lost bromine, resulting in 2-methylpropene (CH₂=C(CH₃)₂).

Reaction:

(CH₃)₃CBr + NaOEt → CH₂=C(CH₃)₂ + NaBr + EtOH

Thus, the major product is 2-Methylpropene.